Facsimile transmitter



Oct. 27, 1953 Filed Oct. 19, 1949 J. H. HACKENBERG FACSIMILE TRANSMITTERINVENTOR.

J.H.HACKENBERG BY MMM,

ATTORNEY Oct; 27r 1953 Filed 0st. 19, 1949 J. H. HACKENBERG FACSIMILETRANSMITTER 16 Sheets-Sheet 2 FIG.2

I'lllllmm INVENTOR.

J.H. HACKENBERG ATTORNEY Oct. 27, 1953 J. H. HACKENBERG 2,657,259

FACSIMILE TRANSMITTER Filed Oct. 19, 1949 16 Sheets-Sheet 3 rol :or

A INVENTOR.

J.H.HACKENBERG 15 |62 l ,2 -BY ATTORNEY 0Ct 27, 1953 J. H. HACKENBERG2,657,259

FACSIMILE TRANSMITTER Filed Oct. 19, 1949 16 Sheets-Sheet 4 ll-iAHACKENBERG ATTORNEY Oct. 27, 1953 J. H. HACKENBERG 2,657,259

FACSIMILE TRANSMITTER Filed oct. 19, 194s 1e sheets-sheet 5 FIG.5

INVENTOR.

J. H. HACKENBERG ATTORNEY Oct. 27, 1953 J. H" HACKENBERG FACSIMILETRANSMITTER 16 Sheets-Sheet 6 Filed oct. 19, 1 49 PHOTOCELL ATTORNEY Och27, 1953 J. H. HACKENBERG 2,657,259

FAcsIMILE TRANsuITTER Filed Oct. 19, 19.49 16 Sheets-Sheet 7 168 |69 AINVENTOR.

J.H.HACKENBERG BY l ATTORNEY Oct. 27, '1953 J ..H. HACKENBERG 2,657,259

FACSIMILE TRANSMITTER Filed Oct. 19, 1949 16 Sheets-Sheet 8 Sinq @1s-lm"lill 75 60 El INVEN TOR.

J.H.HACKENBERG ATTORNEY Filed Oct. 19, 1949 16 Sheets-Sheet 9 FIC-3.9

FIG 9 I2 '62 JNVENToR.

J.H. HACKENBERG BY MMP ATTORNEY Filed Oct. 19, 1949 16 Sheets-Sheet lOFIG. IO

INVENTR.

J. H. HACKENBERG ATTORNEY Oct. 27, 1953 J. H. HAclgl-:NBERG FACSIMILETRANSMITTER' Filed oct. 19, 1949 16 Sheets-Sheet ll FIG. Il

INVENTOR.

J.H. HACKENBERG ATTORNEY Oct. 27, 1953 J. H. HACKENBERG 2,657,259

FACSIMILE TRANSMITTER INVENTOR. |75 |74 J.H.HACKENBERG BYMW ATTORNEYOct. 27, 1953 Filed Oct. 19, 1949 J. H. HACKENBER'G FACSIMILETRANSMITTER 16 Sheets-Sheet l5 INVENTOR. J.H.HACKENBERG ATTORNEY Oct.27, 1953 J. H. HACKENBER'G FACSIMILE TNSMITTER 16 Sheets-Sheet 14 FiledOct. 19, l949 FIG.|4

.vvVEA/Toze.v

J. H. HACKENBERG BY% ATTORNEY Oct. 27, 1953 J, H. HACK'ENBERG FACSIMILETRANSMITTER 16 Sheets-Sheet 16 Filed Oct. 19. 1949 IIS Flags:

INVENTOR.

J. H.HACKENBERG BYM/b- ATTORNEY Patented Oct. 27, 1953 FACSIMILETRANSMITTER John H. Hackenberg, Flushing, N. Y., assignor to The WesternUnion Telegraph Company, New York, N. Y., a corporation of New YorkApplication October 19, 1949, Serial No. 122,326

23 Claims.

My invention is for a novel construction of facsimile transmitterespecially adapted for concentrator use in a main telegraph voffice forsending messages over subscribers lines to their own facsimilerecorders. In a concentrator system of this kind it is desirable to havea number of such transmitters within easy reach of one operator and forthis purpose it is neeccsary that the machines have the smallesthorizontal dimensions possible.

Accordingly I have developed a transmitter of compact columnar structurein which the general disposition of the various parts is in a verticaldirection. One of the Yimportant features of this machine is a verticalscanning drum located in a recess at the front and supported in novelmountings which allow a quick and easy insertion and removal of thedrum. These mountings for the drum are such vthat the mere placing ofthe message carrying drum into scanning position connects it with thedriving mechanism of the machine.

The message sheet on the drum is scanned by an optical carriagesupported back of the drum for vertical sliding movement and operated bya feed screw geared to the same driving mechanism that rotates the drum.The scanning carriage is connected to the lfeed screw by a half nutmounted on a spring arm which normally holds the nut pressed against thefeed screw. A vertical cam shaft operated by a solenoid disengages thehalf nut and frees the carriage for quick return upward. rlhis cam shaftperforms the additional function of automatically retracting certainparts of the scanning carriage out of the way of the drum during thereturn of the carriage.

In addition there are certain switches in the machine for automaticoperation by the drum and the scanning carriage to enable the machine tocarry out its intended function, as will be explained in detail.

Owing to the novel construction, arrangement and operative relation ofthe parts comprising' this machine, the entire apparatus can be mountedon a single narrow frame with a horizontal space of about seven incheswide, so that as many as six machines can be placed side by side forattention by one operator. The practical advantages and various novelfeatures of my invention will be fully understood from a description ofthe accompanying drawings which illustrate a machine as actually builtand operated. In these drawings:

Fig. l shows the machine in perspective;

Fig. 2 is a top plan view with the cover removed;

Figs. 3 and 4, which join on line A-A, .together represent a front viewof the machine, with certain parts in front broken away .to reveal themechanism behind;

Figs. 5 and 6, which join on line B-IB, show a side elevation of themachine as seen from vthe right;

Fig. 6A is a diagram illustrating the :circuits controlled by certainautomatic switches;

Figs. l and 8, which join on line C--C, show a rear view of the machine;

Fig. 9 is a left side view of the upper portion of the machine;

Fig. 9A represents a section on line 9A--9A of Fig. 9;

Fig. 10 shows a plan View sectioned on line rfic-Iii of Fig. 3;

Fig. l1 is a plan view sectioned on lin'e H-I I of Fig. 4;

Fig. 11A shows a switch operating detail connected with the upper drummounting;

Figs. l2 and 13, which join on line D-D, represent a sectional side viewof the machine lookving from right to left, the section being takenapproximately along the lines |2--l2 and I3--l3 of Figs. 3 and 4,repspectively;

Figs. 12A and 12B are sections on line l2c- |2ct of Fig. 12, Fig, 12Ashowing certain parts in normal position and Fig. 12B showing the sameparts in operated position;

Fig. 12C is a section on line I2C-I2C of Fig. 12;

Fig. 12D is a front view of Fig. 12C without the drum;

Fig. 13A shows the cam shaft that operates the half nut of the scanningcarriage;

Figs. 14 and 15 are sectional views on lines |4-I4 and lli-l5,respectively, of Fig. 4, looking in the direction of the arrows;

Fig. 16 shows the bottom of the scanning drum;

Fig. 1'7 is a detached perspective of the frame on which all parts ofthe machine are mounted;

Fig. 18 is a plan view of the phasing magnet assembly with the armaturein operative position;

Fig. 19 is a view similar to Fig. 18 with the armature in releasedposition;

Fig. 20 is a side view of Fig. 19 looking from right to left;

Fig. 21 shows a detail on the vertical section line 2|-2I of Fig. 4; and

Figs. 22, 23 and 24 show the scanning carriage frame in plan, front andside views, respectively.

As this machine was primarily designed to operate with a verticalscanning drum adapted to be easily inserted and removed, it will beexpedient to describe the drum construction rst. Referring mainly toFigs. 12 and 13, the drum I2 is a length of tubing provided with enddisks I3 and I4 which are secured to the tube any practical way, as bypins I5. The parts I2, I3 and I4 are usually made of aluminum. I'ihe topdisk I3 is provided with a central bushing i6 formed with a conicalbearing recess I1. The bottom disk I4 (Figs. 13 and 16) has a centralpivot socket I 8 and an annular groove or channel I9. A drive block 23is secured in groove I9 by a screw 2| and a fixed pin 22 may be added toengage one side of the block as an abutment. The function of block 29,which is easily replaced when worn, will be explained at the propertime. Let it be noted that the block 23 and pin 22 do not project belowthe disk I4.

Attention is called to the fiat faces of the end disks I3 and I4. Thatis to say, the upper disk I3 has a flat top'l and the lower disk I4 hasa fiat bottom I4 so that the drum can stand upright on either end whenout oi the machine (see Fig. l). This is important in the concentratoruse of the transmitter, because the operator can load a number of thesedrums with messages and place them side by side within easy reach forinsertion into this or that machine. Furthermore, since the telegramblanks 23 are mounted horizontally on the drum (see Fig. 1), themessages on the loaded drums are in readable position and the operatorcan instantly pick up the drum she wants.

The end disks I3 and I4 are provided with peripheral flanges 24 whichperform a safety function in the handling of the drum. As shown in Figs.1 and 5, the message blanks 23 are held on the drum by spring garters 25which are made of fine wire coils so as to roll easily over the paper.The flanges 24 extend beyond the garters 2'5, so that accidentaldropping of the drum will prevent damage to the garters. An additionalfunction of the flanges 24 during the insertion of the loaded drum intothe machine will be described later on. In wrapping a sheet around thedrum, the operator places the left edge 23a (Fig. l) on a line 26 markedlengthwise on the drum, as by cutting a thin groove and filling it witha suitable pigment. The right edge 2319 f the sheet overlaps the leftedge because in this machine the drum rotates from right to left as seenfrom the front, or clockwise as viewed from the top. After the sheet hasthus been wrapped around the drum, the spring garters are rolled over itto hold it rmly in place.

As previously mentioned, one of the objects of this invention is toprovide novel mountings for the drum whereby the mere insertion of thedrum into the machine automatically connects it with the drivingmechanism. How that is accomplished will now be described.

All parts of the transmitter are mounted directly or indirectly on anarrow upright frame which is preferably a single casting of aluminum asshown in Fig. 17. This casting comprises a pair of sides 21 and 28, atop piece 29, a partition 30, and a base plate 3|. The top 29 isprovided with an integral bracket 32 for a purpose to be presentlyexplained. The tall narrow chamber 33 between the cross pieces 29 and 30provides room for the optical scanner and the vertical drum, while thebottom chamber 34 of the casting accommodates the driving mechanism forthe scanner and the lower mountingr of the drum.

The drum mounting cmd drive connections Referring to Fig. 13, there is avertical shaft journalled in the cross plates 30 and 3l of the maincasting. The conical top 35 of shaft 35 is shaped to fit into the pivotsocket I8 on the bottom of drum I2. On the upper portion of shaft 35 isfixed a sleeve 36 which carries a collar 31. A drive pin or taper pin 38secures the parts 36 and 31 to the shaft 35. A disk 39 is attached tothe top of sleeve 35 by a forced fit or otherwise, so that the disk 39always rotates with shaft 35. As best shown in Fig. 14, the disk 39 iscut away to provide a segmental gap or opening 40 of considerable width.

In the space between the collar 31 and the disk 39 there is a short arm4I rotatably mounted on sleeve 36 by means of a hub 42 from which thearm projects as an integral extension. The arm 4I carries a pin 43arranged to engage the radial shoulder 49' of disk 39, as seen in Fig.14. Underneath the disk 39 there is a strong contractile spring 44 whichis fastened at one end to a stud 45 on disk 39 and the other end of thisspring is attached to a loop or hook 46 on arm 4|, as shown in Fig. l5.The pull of spring 44 holds the pin 43 against the shoulder 49 of thedisk 39. It is clear from this that the spring 44 constitutes aresilient connection between the shaft 35 and the arm 4 I.

Still referring to Figs. 13, 14 and 15, the arm 4I carries a heavy pin41 which is slidably mounted in a hole 4B of the arm and is normallypushed up through the segmental recess 4U of disk 39 by suitable springmeans. The lower end of pin 41 carries a cross bar 49 which is connectedat its ends to a pair of ccntracting coil springs 5I) (see Fig. 4). Theupper ends of these springs are secured to a pair of side lugs 5Iprojecting from the arm 4 I. The cross bar 49 limits the upward movementof pin 41 which is so arranged as to extend freely into the annularchannel I9 in the bottom disk I4 of the drum (Fig. 13). It is apparentfrom Figs. 14 and l5 that when the pin 41 on the rotating arm 4I engagesthe block 23 in the drum channel I9, the drum is coupled to the driveshaft 35 through the resilient connection 44. I shall have more to sayabout this after describing the drive connections for shaft 3'5.

The reason for supporting the pin 41 in a depressible mounting is this.Since the drum can be inserted in any angular position, it may happenthat the block 23 will come directly over the pin 41. In that event thepin will be depressed so as not to interfere with the proper insertionof the drum. When the arm 4E starts to rotate (as will be describedlater on) the pin 41 slides from under the block 23 and snaps up intothe recess I9 of the stationary drum in position to encounter the block29 as the arm continues to rotate.

Below the partition or cross plate 3U of themain casting, as shown inFig. 13, the vertical shaft 35 has mounted thereon a drive unitcomprising a sleeve 52 rotatable on the shaft, a worm gear 53 secured tothe lower end of the sleeve, and a ratchet wheel 54 fastened to theupper end of the sleeve. A collar 55 holds the drive unit in place. Asshown in Figs. 4 and 11, the worm gear 53 is in mesh with a worm 56 onthe shaft 51 of a synchronous motor 58 mounted in the bottom chamber 34of the main casting. rlhe motor is attached to the right panel 29 of thecasting by screws '59 (Fig. 6). It will be clear from the foregoing thatthe drive unit 52-53-'54 is permanently geared to the motor and isnormally free to rotate on shaft 35.

The driving connection between shaft 35 and gear 53 is effected throughthe ratchet wheel 54 by a clutch assembly 80 frictionally mounted onsleeve 52 so as to be capable of remaining stationary while the sleeverotates. Referring to Figs. 4 and 13, this clutch assembly comprises ayoke 5| which fits halfway around the shaft 35, a semicircular frictionwasher 52 arranged opposite the yoke 6|, and a strong coil spring 63 forholding the washer (usually of felt) pressed against the shaft. Thespring 63 is attached at its ends to lugs E4 on yoke 6 I. Thisparticular form of friction clutch is old and any other kind of slipclutch may be used.

The yoke 5| has a slotted arm 55 (Fig. 21) which may be an integralextension of the yoke. The slotted end of arm 65 carries a cross pin 86on which a pawl or trigger 61 is pivoted. Avtorsion spring 68 isattached to the cross pin 66 and passes under the trigger 81 (Fig. 4) torock it into locking engagement with the peripheral teeth of the ratchetwheel 64. Assuming that the trigger S1 connects with the ratchet wheel54, it is obvious that the trigger is locked to the motor driven sleeve52 by a direct mechanical connection'. The function of trigger 81 is tocouple the drum shaft 35 to the motor '58 at the phasing moment of themachine, as will now be described.

Referring to Figs. 4, 18, 19 and 20, an angle bracket 89 secured to theside wall 21 of the main casting supports an electromagnet 18 which isthe phasing magnet of the machine. The bracket 69 is attached to thecasing by screws 1| and the magnet is fastened to the bracket by screws12. The base of magnet 10 projects into an opening 13 of the casting soas to permit disposal of the magnet assembly within a minimum space. Abracket 14 is attached to the rear side o1' the magnet frame by screws15 and is provided with a pair of lateral flanges 16 (see Fig. 8) 'whichsupport a pin 11 as a pivot mounting for the armature bar 18.

A Ushaped strip 19 is secured to the rear end of the armature 18 and haslateral ears .or lugs 88 (Fig. 8) through which the pin 11 passesloosely so that the armature is free to rock about the pin. Acontractile spring 8| is connected at one end to a lug 82 on plate 14and at the other end to an extension 83 of the armature. The lug 82 maybe held in place by one of the screws (Fig. 19). The constant tendencyof spring 8| is to rock the armature 18 away from the magnet and thismovement is limited by a stop 84 arranged to engage an adjustable screw84 on the armature bar 18. The stop 84 is shown in Fig. 19 as anintegral angular iiauge formed on the plate 14, but it may be a separatepiece adjustable to controlthe amount of travel of the armature. Whenthe magnet 18 is energized, the armature 18 is rocked against the magnet(Fig. 18) and this movement of the armature is limited by an adjustablescrew 85, which is a non-magnetic stop to maintain a small air gapbetween the armature and the polar faces of the magnet, so that theresidual magnetism will not freeze the armature in closed position afterthe current is shut off.

As shown in Fig. 2o, the armature bar 1a is formed at its free end withan inclined edge 86 which ends in a square shoulder 81 adapted toreceive a projection or tooth 88 on the trigger 81 when the magnet 10 isnot energized, This will be clear from Figs. 4 and 19. The inclined edge86 on the armature guides the trigger tooth 88 against the lockingshoulder 81 which holds the trigger out of contact with ratchet wheel 54against the action of torsion spring 68. In other words, as long as themagnet 18 is not energized, the friction clutch 60 is held stationary bythe interlocking of trigger 61 with the armature 18 while the ratchetwheel 54 is being rotated by the motor 58.

When the magnet 10 is energized, its armature releases the trigger 61(Fig. 18) which is instantly thrown into engagement with the ratchetwheel 54 by the spring 88. The trigger now rotates with the motor drivenratchet wheel as a peripheral projection thereof. However, the drumshaft remains disconnected from the ratchet wheel 54 until the trigger61 strikes a dog 89 xed on the drum shaft. The dog 89 is shown as anextension on a block or collar 9D secured on shaft 35 by a set screw 9|(Fig. 13) by which the angular position of the dog can be properlyadjusted.

Referring to Fig. 18, where the armature 18 is shown in operatedposition and the trigger 61 is in engagement with the ratchet wheel 54,it will be seen that when the trigger strikes the clutch dog 89 (asindicated at 61'), the drum shaft 35 becomes coupled to the synchronousmotor 58 through the driving unit 52-5354- Consequently, when the pin 41on arm 4| strikes the block 28 on the bottom of the drum (see Fig. 16),the drum is coupled to the shaft 35 through the spring 44 which takes upthe shock of the coupling.

Since the Vertical drum |2 is driven at its lower end by a live centerassembly on the shaft 35, the upper end of the drum need only besupported by a dead center, which is shown in Fig. 12 as a pivot pin orshaft 92 mounted reciprocably in the top bracket 32 of the main casting.The shaft 92 does not rotate, for its function is merely to hold thedrum centralized. An expanding coil spring 93 constantly tends to pushthe shaft 92 downward so that the conical end 92 of the shaft restsfirmly in the bearing socket l1 of the drum. The spring 93 also holdsthe socket I8' on the bottom of drum I2 pressed against the pivot point35 of shaft 35. An adjustable collar 94 on shaft 92 permits regulationof the spring pressure to the desired degree. When there is no drum inthe machine, the downward movement of shaft 92 under the action ofspring 93 is limited by a stop 95 on bracket 32 below the collar 94. Thestop 95 is preferably a felt washer to deaden the noise.

I have made special provisions for simplifying the insertion of the drumby guiding it toward its central position. For this purpose the pivotshaft 92 carries a guide flange 913 secured to the lower end of theshaft by means of a collar 91 which is fixed on the shaft by a drive pinor taper pin 98. The iiange 96, which is fastened to the underside ofcollar 91 by rivets 99, is a piece of sheet metal .in the shape of ahalf disk that extends forward. and flares upward along its edge, asbest shown in Figs. 1, 10 and 12. Co-operating with the flange 98 aretwo guide rods |88 arranged on opposite sides of the fiange andconverging toward it, as seen in Fig. 1. The rods I 88 are attached attheir lower ends to the sides of the main casting by screws 10|, and thetop ends of the rods may simply enter holes or recesses |02 (Fig. 3) inthe underside of the top plate 29 of the casting.

Looking at Fig. 1, it will be apparent that 7 when the top edge of thedrum strikes either rod |00, it will be automatically guided toward theprojecting flange 96 which will he pushed up and guide the drum tocentral position for receiving the pivot end 92' of shaft 92. Let it benoted here that in this operation of inserting a message bearing drum,the flanges 24 (particularly that of the top disk i3) assist in guidingthe drum into position by providing a smooth surface to glide over theflange 96 and the guide rods |00. While the drum is being inserted, theflanges 24 also provide protection for the message blank and prevent thespring garters 25 from being shifted out of position. With a littlepractice the operator can insert the drum in a moment without evenlooking at the machine. The upward movement of shaft 92 when theoperator pushes the drum against the ilange 96 is limited by the collar91 striking the lower bearing |03 of the slidable shaft e2. A feltwasher |04 on collar 91 deadens the noise of this operation. As seen inFig. l0, the rods |90 extend adjacent to the ends of the guide disk 05and act as stops to prevent rotation of the dead center 92 withoutinterfering with its slidable movements. A suitable brake |05 is mountedon the guide disk 96 `and presses against the nat smooth top of the drumto act as a steadying friction load thereon, to ensure that the drivepin 41 is rmly engaged against the block (Fig. 16) at all times.

Let it be noted that the reciprocable dead center 92 of the drumoccupies three different vertical positions, First, its normal orlowermost position occurs when there is no drum in the machine and thecollar 94 rests on the stop washer 95, as shown in Fig. 3. The uppermostposition of shaft 92 occurs when the operator pushes a drum against theguide disk 96 and thereby lifts the shaft until the washer |04 strikesthe bearing |03. The third. position of shaft 92 is intermediate of itstwo extreme positions and represents the operative or drum holdingposition as shown in Fig. 12. In Fig. 11A the dotted outlines 94a. and94h of collar 94 correspond to the lowest and highest positions of shaft92, while the full-line showing of collar 94 represents the drum holdingposition of the shaft.

I utilize the various positions of shaft 92 to control a suitable switch|06 mounted on the top plate 29 of the main casting. The construction ofthis switch is immaterial and it is sufiicient to say that it has a pairof normally open contacts |01 (see Fig. 3) which are closed by a pivotedarm |08 outside the switch casing. The free end of arm |00 carries aroller |09 arranged in the path of a. pin ||0 projecting from the collar94 on shaft 92. The arm |00 normally hangs in position to keep theswitch open. When the shaft 92 is in normal or lowermost position, thepin I0 is below the roller |09 and the switch |06 is open. The same istrue when the shaft 92 is in uppermost position, for then the pin 0 isabove the switch arm |08.

When a drum is inserted and the shaft 92 is pushed up, the pin ||0 movespast the roller |09 from position ||0a in Fig. 11A to position ||0b,

whereby the switch arm |08 is momentarily operated to close the switch|06. However, this brief closing of the switch has no effect on themachine for reasons that need not be explained here because the circuitscontrolled by switch |06 are not a part of the present invention. It isonly when the drum is in proper position in the machine that the switch|06 is held closed by the pin I0 to keep the power on the machine, asindicated schematically in the circuit diagram, Fig. 6A. Actually, oneor more control relays are interposed between switch |06 and the powerlines, but that is not a part of this invention. It will be understood,then, that unless a drum is in the machine, the power is cut off and themere insertion of the drum automatically connects the machine to itslocal source of power.

When inserting a loaded drum, the operator need pay no attention to theangular position of the drum, because it will always start to rotate inless than one turn of shaft 35 after the trigger 51 has been released bythe `phasing magnet 10 and become coupled to the clutch dog 89. There isa xed angular relation between the dog 89. the pin 41 and the overlap ofthe mounted blank. As previously explained (see Fig. l), the right edgeof the mounted blank coincides with the longitudinal line 26 on the drumand that line is in xed relation to the block 20. In this case (see Fig.16) line 26 is in the radial plane of the forward edge 20 of block 20but those two elements may be placed in any other fixed relation. Thepoint to bear in mind is that when the driving pin 41 strikes the block20, the message sheet is always in the same angular position relative tothe driving pin.

It will be clear from the foregoing explanation that when the phasingmagnet 10 is energized, the released trigger 61 will engage the dog 89in less than one turn of the ratchet wheel 54 to start rotation of shaft35, and in less than one turn of this shaft the pin 41 will strike theblock 20 to start the drum rotating. Of course, the particular anglethrough which the shaft 35 turns before the pin 41 picks up the drumdepends on the angular position of block 20 when the drum is inserted.But in any case that angle will always be less than 360. This slightlyvariable time interval (exceedingly small) between the operation ofmagnet 10 and the start of drum l2 by the pin 41 is immaterial in theproper phasing of the transmitter with the connected receiver. Since theclutch 60 is of the positive action type, the phasing error is in no waydependent upon what might be a variable friction between the drivensleeve 52 and the clutch assembly.

The optical scanning mechanism The parts that comprise the opticalscanner of my machine are mounted on a slidable carriage SK which isshown separately in Figs. 22 to 24 as a sheet metal frame constructionto support the various parts in operative relation. This carriage framecomprises two main plates, a right-angled front plate |2| I3 and a sideplate |4 which is welded to the angular section ||3 of the front plate.In the angle of the front plate is secured a tube |I5, as by brazing italong the sides at H5. The tube ||5 contains a pair of bushings ||6 forslidably mounting the carriage on a vertical guide rod |1. This rod isxed at its ends in the horizontal plates 29 and 30 of the main casting,as shown in Figs. 5 and 13.

Again referring to Figs. 22-24, a right-angled bar ||8| |9 is welded tothe side plate ||4 and to an integral lug |20 on plate ||2. A dependingbracket |2| is welded to the front arm I8 and is provided at its endswith lateral nanges |22 for a purpose that will appear later. An angularmetal strap |23 (Fig. 10) is attached to the arm I8 by screws |24 whichenter holes |25

